Abrasive disk package



July 23, 1968 BEERs 3,393,798

ABRASIVE DISK PACKAGE Filed Aug. 19, 1965 INVENTOR eoeae 7" Al. was,

ATTORNEY United States Patent O 3,393,798 ABRASIVE DISK PACKAGE Robert N. Beers, Niagara Falls, N.Y., assignor to The Carborundum Company, Niagara Falls, N.Y., a corporation of Delaware Filed Aug. 19, 1965, Ser. No. 480,851 9 Claims. (Cl. 206-60) ABSTRACT OF THE DISCLOSURE A package of thin abrasive disks comprising a stack of disks in a moisture impervious container. The container comprises a cylindrical tube with a bottom enclosing one end of the tube and a removable top fitting tightly over the opposite end of the tube.

This invention relates to packaging and, more particularly, to a package of thin abrasive disks.

One type of abrasive disk that is in common usage has a paper or cloth backing and abrasive particles or grit covering the face of the disk. The abrasive particles are bonded to the backing by means of a resin which is applied in the form of a coating over the entire face of the disk.

It is customary practice to mount these abrasive disks on a fiat, rotary face plate which forms a rigid backing for the disk. The disk is thin and flexible and therefore requires the support of the face plate in order to apply the necessary grinding pressure against the workpiece. The abrasive disk usually has a hole at the center to fit over a mounting stud and is clamped against the face plate by a washer at the center of the rotary face plate. The disk usually is not secured in any manner around the periphery of the face plate and therefore it is necessary for the disk to have a slight curvature which is concave on the backing side of the disk.

The concave shape of the abrasive disk causes the peripheral edge of the disk to be urged against the face plate around the rim where the center of the disk is clamped against the face plate by means of a conventional nut and washer. When the face plate and disk are rotated, the peripheral edge of the abrasive disk tends to remain pressed against the face plate.

One serious problem encountered in shipping and storing resin bond abrasive disks is the warping or curling of the disks. The backing material in the disks is hygroscopic, but the face of each disk is coated with a resin and is imprevious to moisture. Changes in moisture in the air to which the backing material is exposed cause the backing material to shrink. Since the front of the backing material is coated with a resin it is dimensionally stable. As a result, the disks tend to curl up. A disk may curl so tightly that the opposite edges of the disk engage each other. When the disks are curled, they are unsuitable for most grinding operations, since the disks have lost the concave shape and do not lie flat against the face plate. Attempts have been made to overcome this problem by coating the backing material with a sizing solution to reduce the absorption of moisture into the material. These attempts, however, have not proven satisfactory.

Various devices have been used in packaging abrasive disks in order to prevent them from curling. One suggestion has been to use a spindle that passes through the center hole of the abrasive disks with a large head on one end and utilizing a separate washer on the opposite end of the spindle for clamping the abrasive disks tightly between the washer and the head of the spindle. A pin or other means may be used for securing the washer on the spindle. This device reduces the tendency of the disks to curl, but it is awkward to use. Another suggestion has 'ice been to seal the disks in a moisture-proof bag. The abrasive on the disks, however, quickly wears through the bag and causes the bag to tear. Also, after the seal on the bag is broken, the moisture freely enters the bag and may cause the disk to curl between the time that the first and the last disks are removed from the bag.

In view of the defects of previous packages for resin coated abrasive disks, it is an object of this invention to provide an improved abrasive disk package.

It is a further object of this invention to provide an abrasive disk package in which the disks remain in their desired concave shape.

It is a still further object of this invention to provide a package for shipping and storing a plurality of abrasive disks from which a disk may be readily removed, without exposing the remaining abrasive disks to excessive moisture.

These objects are accomplished in accordance with a preferred embodiment of the invention by an abrasive disk package in the form of a cylindrical tube with a bottom enclosing one end of the tube and a removable top fitting tightly over the opposite end of the tube. The side wall of the tube has an inner lamina of heavy paper or cardboard, with an intermediate lamina of moisture impervious sheet material, such as aluminum foil, and the other lamina is formed of heavy paper or cardboard. The internal diameter of the tube is slightly larger than the outer diameter of the abrasive disks and the disks are stacked in the tube between the bottom and the top.

This preferred embodiment is illustrated in the accompanying drawings in which:

FIG. 1 is a side elevational view, partially in cross section, of the package of this invention; and

FIG. 2 is an enlarged detail view of a portion of the package.

A package 2 of abrasive disks in accordance with this invention is illustrated in FIGS. 1 and 2. The package 2 includes a cylindrical tube 4. The tube 4 has a bottom 6 in the form of a rigid circular plate that is impervious and preferably formed of metal. A rim 8 is formed on the bottom 6 and the rim has a channel 10 for receiving one end of the tube 4. The opposite sides of the rim 8 are crimped toward each other to secure the tube in the channel 10. A plurality of abrasive disks 12 are supported on the bottom 6 of the package. The disks 12 have a paper or fabric backing and have one face covered with a layer of abrasive grit which is bonded to the backing by a resin coating. The abrasive disks 12 are slightly spherical, and the lowermost disk engages the bottom 6 along the peripheral edge of the disk, while the center of the disk is spaced above the bottom 6. All of the disks have substantially the same shape, so that there is no tendency for the disk to become flattened by the weight of other disks piled on top of it. The internal diameter of the tube 4 is slightly larger than the diameter of the disks to provide sufiicient clearance for removal of the disks from the package, but the tube has a sufiiciently small diameter to restrict lateral displacement of the disks.

The tube 4 is laminated of metal foil 14 which is sandwiched between an interior layer 16 and an exterior layer 18 of fibrous material, such as heavy paper or cardboard. Preferably, the tube is spiral wound with an interior layer 16 of jute paper of the order of .022 inch thickness, a layer of aluminum foil of .0035 inch thickness and the exterior layer 18 of 30 pound weight heavy kraft paper. The metal foil 14 acts as a moisture barrier to prevent the entry of moisture into the interior of the package, while the interior layer of paper protects the metal foil from abrasion by the disks 12. Otherwise, the abrasive grit on the disks would quickly wear through the metal foil and destroy its effectiveness. Although the peripheral edges of the disks 12 fit closely adjacent the interior surface of the paper layer 16, there is space for slight lateral movement of the disks against the paper, but the interior laminate is sufficiently thick to prevent the abrasive disk from wearing through the paper and the metal foil.

The top of the package is closed by a lid 20, which is preferably formed of metal. The lid 20 has a recessed rim 22 and the edge 24 of the lid 20 is flared outwardly to facilitate pressing the lid over the end of the tube 4. A sheet of heavy paper may be placed on the uppermost disk to protect the lid from the abrasive grain and also to act as a filler. The lid 20 fits tightly around the tube 4 to prevent the entry of moisture between the lid and the tube. The lid may be secured to the tube by a tape (not shown) extending around the edge 24 and bonded to the lid and the tube. The tape is removed when the package is opened for the first time.

The recessed rim 22 of the lid 20 is adapted to receive the rim 8 of the bottom 6 of another package, so that the packages may be easily stacked one on top of the other. The cooperation of the lid 20 and the bottom 6 causes the packages to be centered and resists accidental displacement of a stack of packages 2.

The abrasive package of this invention protects the abrasive disks 12 from moisture and physical damage. Consequently, the disks retain their desired shape. The lid 20 is easily removed and the disks may be withdrawn one at a time, as needed. The package then may be resealed merely by replacing the lid 20. The packages themselves may be easily stacked on top of each other because the depressed rim 22 on the lid 20 allows the bottom of another container to rest on the center portion of the lid 20 with the rim 8 directly above the rim 22.

While this invention has been illustrated and described in one embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.

I claim:

1. A package of abrasive disks comprising a plurality of disks each having a backing on one side of the disk and having abrasive grit bonded to the other face of said disk, said disks being stacked in substantially axial align ment, a cylindrical tube extending around the circumference of said disks, a bottom closing one end of said tube, and a lid closing the opposite end of said tube, said bottom and lid and tube being impervious to moisture.

2. A package of abrasive disks comprising a plurality of disks each having a backing on one side of the disk and having abrasive grit bonded to the other face of said disk, said disks being stacked in substantially axial alignment, a cylindrical tube extending around the circumference of said disks, a bottom closing one end of said tube, said disks being of substantially uniform thickness and being concave on the backing side, said disks having the backing side facing said bottom, and a lid closing the opposite end of said tube, said bottom and lid and tube being impervious to moisture.

3. A package abrasive disks comprising a plurality of disks each having a backing on one side of the disk and having abrasive grit bonded to the other face of said disk, said disks being stacked in substantially axial alignment, a cylindrical tube extending around the circumference of said disks, a bottom closing one end of said tube, and a lid closing the opposite end of said tube, said tube having a fibrous inner surface and being impervious to moisture, said lid and bottom being impervious to moisture.

4. A package of abrasive disks comprising a plurality of disks each having a backing on one side of the disk and abrasive grit bonded to the other face of said disk, said disks being stacked in substantially axial alignment, a cylindrical tube extending around the circumference of said disks, a bottom closing one end of said tube, and a lid closing the opposite end of said tube, said tube having an outer layer and an inner layer of fibrous material and an intermediate layer of metal foil, said lid and bottom being impervious to moisture.

5. A package of abrasive disks comprising a plurality of disks each having a backing on one side of the disk and having abrasive grit bonded to the other face of said disk, said disks being stacked in substantially axial alignment, a cylindrical tube extending around the circumference of said disks, a bottom closing one end of said tube, and a lid closing the opposite end of said tube, said bottom having a channel formed in the rim thereof, said tube extending into said channel, and means for securing said tube in said channel, said bottom and lid and tube being impervious to moisture.

6. A package of abrasive disks comprising a plurality of disks each having a backing on one side of the disk and having abrasive grit bonded to the other face of said disk, said disks being stacked in substantially axial alignment, a cylindrical tube extending around the circumference of said disks, a bottom closing one end of said tube and having a rim projecting below the center portion of said bottom, a lid closing the opposite end of said tube, said lid having a rim extending around the periphery thereof, said rim being displaced below the central portion of said lid and engaging over the end of said tube, said bottom and lid and tube being impervious to moisture, whereby the bottom rim is received on said lid when packages are stacked on top of each other.

7. A package of abrasive disks comprising a plurality of disks each having a backing on One side of the disk and having abrasive grit bonded to the other face of said disk, said disks being stacked in substantially axial alignment, a cylindrical tube extending around the circumference of said disks, a bottom closing one end of said tube, a lid closing the opposite end of said tube, said disks being of substantially uniform thickness and being concave on the backing side, said disks having the backing side facing said bottom, said tube having an inner surface of fibrous material and being impervious to moisture, said bottom and lid being impervious to moisture.

8. A package of abrasive disks comprising a plurality of disks each having a backing on one side of the disk and having abrasive grit bonded to the other face of said disk, said disks being concave on the backing side and being of substantially uniform thickness, said disks being arranged in a stack with the backing side of each disk facing the bottom of the stack, a tube enclosing the peripheral edges of said disks, a bottom closing an end of said tube, said bottom having a recessed central portion and a rim projecting axially from the tube, and a lid closing the opposite end of said tube, said lid having a recessed rim, said tube including an outer layer and an inner layer of fibrous material and an intermediate layer of moisture impervious sheet material, said top and bottom being impervious to moisture.

9. A method of packaging abrasive disks having a backing side and an abrasive side comprising arranging the disks in a stack with the backing side of each disk facing the bottom of the stack, placing the stack of disks in a container with the bottom of the stack resting on the bottom of the container, said container having a tubular side wall with a fibrous inner surface, and closing said container with a lid, said lid and bottom and tube being impervious to moisture.

References Cited UNITED STATES PATENTS 466,991 1/1892 Kleinfeldt et a1. 220-27 679,171 7/1901 Jones 229-35 2,268,245 12/1941 Davis 206-46 3,053,384 9/1962 Loomis 20646 MARTHA L. RICE, Primary Examiner. 

